[SPAM] The system halted between MSP430 and TPS3823

Hello~all, I would like to ask some advice from you.
When I tested the MSP430,the slice I use is 149 and the reset chip I used is TPS3823. The aim I tested it is to assure the accuracy of outside watchdog.The program is simple while there is just one timer and a serial port to send data.But the MCU crashed ! I don’t know why ?! If the 149 also was subjected to crash,here the signal of feeding the dog would not be produced.The TPS3823 should produce the reset signal as well. Was the TPS3823 crashed?
This is the TPS3823 datasheet: (mod removed spam link) Can you help me or give me some advice?
Thanks a lot.
Wishes~